An apparatus of this kind having a press fit for a cylindrical sensor head of a pulse-type rotation speed transducer is known for passive pulse-type rotation speed transducers, for example inductive pulse-type rotation speed transducers, in which context the cylindrical sensor head can rotate in the clamping sleeve without considerably influencing or modifying the measurement result.
For active pulse-type rotation speed transducers, however, whose measurement result is orientation-dependent and which operate, for example, with Hall sensors, provision is made for holders with respect to a rotor or magnet wheel which have a screw connection between the holder and sensor head, and which permit neither rotation nor axial displacement of the cylindrical active and orientation-dependent sensor head.
U.S. Pat. No. 5,922,953 discusses an apparatus that operates with an orientation-dependent Hall sensor, the cross section of the sensor head having an axial groove that is in engagement with a spring of a sensor housing surrounding the sensor head and forms a twist prevention system by way of a modification of the cylindrical shape of the sensor head. The sensor housing surrounding the sensor head is moreover connected to a laterally projecting arm that is bolted onto the holder and thus ensures radial immobilization of the sensor housing.
An apparatus of this kind for self-adjustment of a pulse-type rotation speed transducer disadvantageously requires, in addition to the modified active sensor head having an axially aligned groove-spring construction in order to produce a twist prevention system, a further complex and cost-intensive sensor housing in which the sensor head can be axially displaced without changing the radial alignment.
U.S. Pat. No. 4,612,501 discusses an apparatus for self-adjustment of a pulse-type rotation speed transducer in which what is used as a twist prevention system is a clamping ring that, by way of corresponding cutouts that are to be recessed into the cylindrical sensor head, positively ensures rotation between the clamping ring and sensor head. This apparatus has the disadvantage, however, that the clamping ring, with its clamping teeth, can rotate in the smooth bore wall of the holder, and the sensor can thus also rotate in the bore. Reliable radial alignment of an orientation-dependent sensor is thus not obtained, since twist prevention between the holder and clamping ring is not provided here. This apparatus, too, has the disadvantage that the profile of the cylindrical sensor head must be modified in order to ensure at least rotation of the sensor head with respect to the clamping ring.